Stop mechanism



July 19,19z7.

J. H. REED STOP MECHANISM Filed 00in. 14. `1922 Ey hww @Mmm uw Patented `luly 19, 1927.

UNITED STATES l 1,636,324 PATENT OFFICE.

JAMES H. REED, OF SWAMPSCOTT, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO UNITED SHOE MACHINERY CORPORATION, OF PATERSON, NEW JERSEY,

A CORPORATION OF NEW JERSEY.

STOP MECHANISM.

This invention relates to stop mechanisms for automatically stopping a machineat a definite point in its cycle of operations when the usual starting treadle is released or other mechanism operated to release the clutch and disconnect the machine from its source of power.

Mechanisms of this character operate to stop and start a machine quite suddenly, and l0 in the case of heavy machines, orl those operatingat relatively high speed, a considerable blow is struck upon thestop mecha nism when the latter isV operated to stop 'the machine, such a blow not only imposing a considerable shock upon the stop mechanism, but reacting upon the machine itself to the detriment of the latter. A similar blow is struck when the machine is started. The present inventionhas for its objects to provide a construction in whichlboth lof these blows will be cushioned and in which the starting operation isa relatively gradual one, and also to provide stoppingmeans in which the `driven mechanism is given, through a suitable brake, a movement resisting force which is directly Vproportional to the momentum of the parts to be stopped, 'so that, the harder the blow struck, the greater will be the force with which the brake is applied to stopfthe mechanism. The foregoing and other objects of the invention, together with means whereby the same may be carried into effect, will best be understood from the following description trated in the accompanying drawings. It will be understood however that the particular construction and application descrbed and shown have been chosen for illustrative purposes merely, and that the invention, as defined by the claims hereunto appended, may be otherwise practiced without departure from its spirit or scope.

In said drawings:

Fig. 1 is a somewhat conventionalized view, in side elevation, of the head of a shoe sewing machine having 'the invention applied thereto, the clutch being shown` as fully engaged, but'with the stopiinger 1n a position to disengage the same upon a further rotary movement ofthe shaft in the direction of the arrow.

Fig. 2 is` an enlarged side elevation, partof a preferred embodiment thereof illus-k Application filed October 14, 1922. Serial No. 594,458.

1 Fig. 5 is a transverse section taken subn stantially on the line 5--5 of Fig. 4.`

In Figure 1 is indicated the head 10 of a shoe sewing machine having a suitable frame in which is journalled a main shaft 11 driven by power from a siiii'tablesource delivered through a belt (not shown) to a driving pulley 12 loose on said shaft. The pulley 12 has a hub 45 on which is rotatably mounted a ring 44 held in position on said vhub by `a collar 46 secured to the hub 45 and received in the countersunk end of said ring. The pulley 12 carries a laterally projecting pin 47 which enters anr arcuate slot or groove 48 in the adjacent face of the ringy 44, said slot containing a spring 49 interposed bctween said pin and one end ofthe slot, whereby said pin is normally held in engagement with theV opposite end of the slot, as shown in Fig. 5. The ring 44 constitutes the driving element or member of a clutch, the driven member of which comprises a hub 13 fast upon the shaft 11,`as by means of a suitable set screw 14 (see Figure 4). Guided in the hub13 for longitudinal movement parallel to the shaft 11 is a sliding bolt 15 adapted at its forward end to engagea recess 16 in the ring 44, thereby connecting the driving and driven members forrotatiou in unison. The bolt 15 is acted upon at its outer end by a spring 17 housed in a. recess in the outer end of an enlarged portion 29 of the hub 13, said spring'tending normally to force the bolt into engagement with the recess 16 and connect the clutch members. The bolt 15 is form-ed with a head 19 which cooperates with the wedgashaped end 2O of a stop member or finger 21, adapted to enter a groove 22 in the hub 13 and engage` the head 19 when the parts are rotated in the direction indicated by the arrows, causing said head to be forced backwardly or to the left in Figure 2, thereby withdrawingthe bolt 15 from therecess 16, and disconnecting the clutch members. At the base of the wedge-shaped end 20 the stop member 2l is formed with a shoulder 23. which, after the` bolt has been withdrawn to disconnect the clutch members, is engaged by the bolt head 19, thereby positively stopping the driven member and shaft. T he stop linger or member 21 is pivoted by a bolt or cap screw 24 to a lug 28 on the machine frame and may be swung upon its pivot into and out of the groove 22, and to this end is provided with an extension 25 connected by a link 26 to a suitable foot treadle 27 or other operating device whereby said fingi'er may be swung out of theigroove 22 to permit the spring 17 to engage the clutch, said finger being moved into the `groove 22 to disengage the clutch and stop the machine when the treadle is released. and lifted by the usual treadle lifting spring 30.

When the bolt 15 is projected into the recess 16 by the spring 17 to engage the clutch, the machine is at restso that a blow is struck by the end of the recess 1G upon the end of the bolt. This blow is cushioned by the spring A49which is compressed permitting the ring 44 to yield angnlarly with respect to the pulley 12 and the machine to; be started gradually. As thc inertia of the parts is overcome, and the machine picks up Speed, the spring 49 again expands, said spring being of sufficient strength to transmit the necessary power when the machine is running.

The opening 31 in the stop member 21 to receive the pivot bolt 24 is elongated in a direction generally tangential tothe hub 13, and particularly to that portion thereof at the bottom of the groove 22 which is cngaged by said stop finger when the latter is in a position to stop the machine. When. therefore, the shoulder 23 on said stop finger is struck by the head 19 of the clutch bolt, said stop finger will be moved tangentially of the hub under the impact. Such movement is resiliently resisted by a spring pressed abutment in the form of a plunger 83 slidably mounted in a tubular guidc't carried by the frame of the machine, said plunger being backed by a spring having an adjusting screw 36 by which. the tension of said spring may be adjusted. The axis of the plunger 33 and guide 34 is substantially in alinement with the slot 31, so that said plunger tends to yieldingly resist the tangential movement of the stop linger 2l caused by the impact of the bolt head 19, thereby cushioning said impact.

The enlarged portion 29 of the hub 13 constitutes a brake drum which is encircled by a brake band 38 one end of which is fixed by a pin 39 to ahanger 40 loosely hung .on the shaft 11 and a'dju'stably secured ,to the machine frameb a( bolt 41 which passes through a slot 42 1n said hanger. The opposite end of the brake band 3S is secured by a pin 43 to the stop finger 21 at a point eccentric to its pivot 24.

In the foregoing construction, it will be seen that when the stop finger 21 is moved outwardly' to rmit the clutch to be engaged, the bra e band 38 will be loosened, but that when said finger is swung inwardly to stop the machine, said brake band will be tightened upon the brake drum 29. It will also be seen that when the shoulder 23 of the stop finger is struck by the bolt head 19, causing said finger to yield against the pressure ofthe spring 35, this yielding movement, which is in a direction generally tangential to the clutch hub, will cause said brake band to be further tightened to an eX- tent determined by the force of the blow. Since this blow is proportional to the momentum of the parts as transmitted through the driven member or hub 13, it will be seen that the brake band 38 constitutes means for applying to the driven member a movement resisting force which is roportional to such momentum, the final tightening of the brake being effected by the driven member itself acting through the stop finger. The adjustable hanger 4() enables the force with which the brake is applied to be manually adjusted in accordance with the requirements and to compensate for wear.

As will now be seen, the invention above described provides a stop mechanism wherein the blows struck by the sudden stopping and starting of the machine are so completely cushioned as to avoid undue shock to the parts. It will also be seen that the blow struck in stopping is itself made to apply a force tending further to stop the movement of the part which strikes the blow, which stopping force is directly proportional to the force of the blow struck. 1t has been found in practice that, by the use ofthe invention described, all start-ing and stop ing shocks are completely eliminated, wiile permitting the machine to be quickly and accurately stopped at the desired point in its cycle of operations.

What I claim is 1. The combination with ydriving and driven members, of a bolt carried by said driven member for connecting the same with said driving member, a yieldingly mounted stop finger for withdrawing said bolt and stopping said driven member, and a brake for said driven member connected with said stop finger and operated by the yielding movement thereof.

2. The combination with driving and driven members and a headed bolt carried by said driven member and movable into and out of engagement with said driving member, of a stop finger having a wedge rtion to engage the head of saidbolt an withdraw the same from engagement with said (lriving member, said finger having also a shoulder to engage said bolt and stop the rotation of said driven member, a support on which said stop finger is pivoted for movement into and out of a position to engage said bolt as said driven member is rotated, said stop finger having also a movement on said support-in the direction of the blow of said bolt on ,said shoulder, ayielding abutment for resiliently resisting said last named movement and cushioning said blow, and a brake band fixed at one end and encircling a portion of said driven member, the opposite end of said band being oonnected to said stop finger.

3. The combination Withn a frame and a shaft journalled therein and having driven and driving members respectively fast and loose thereon, of means for operatively connecting said members, a stop inger for releasing said connecting means and stopping said driven member, a brake drum on said driven member, a hanger loosely supported by saidshait and adjustably connected With said Jframe, and a brake band secured at one end to said hanger and at the other end to said stop inger, said brake band encircling said brake drum.

4. A clutch mechanism comprising a pulley having a hub, a ring rotatably mounted onsaid hub and formed with a recess and an arcuate slot, a pin carried by said pulley and entering said slot, a spring interposed between said pin and one end of said slot, and a driven member having a sliding boit adapted to enter said recess.

In testimony whereof I affix my signature.

JAMES H. REED. 

